Introduction to Concrete Additives (2)
Russia's insistence on paying for Russian gas in rubles has rattled European countries: Greece held an emergency meeting of suppliers, the Dutch government would urge consumers to use less gas, and the French energy regulator told consumers not to panic. Russian gas meets one-third of Europe's annual energy needs.
Russia said they could expand their demand for ruble payments for other commodities, including oil, grain, fertilizer, coal, and metals, which raised the risk of recession in Europe and the US.
Moscow is expected to unveil its ruble payment plan in early April, but it said it would not immediately ask buyers to pay for gas in rubles.
Western countries have said paying in rubles would be a breach of contract, and renegotiation could take months or longer. This uncertainty has pushed commodity market prices higher.
The supply and prices of other commodities like the Concrete Additive could also be affected.
The concrete additive is a material that can improve the properties of the concrete mixture or hardened concrete by adding not more than 5% of the weight of cement in the process of mixing concrete (except for special circumstances).
Using concrete additives is one of the most effective ways to improve concrete strength, improve performance and save cement and energy.
There are various types of concrete additives. In the last article Introduction to Concrete Additives (1), we talked about concrete water reducers and early strength agents. In this article, the set retarder, the air-entraining agent, and the accelerating agent are going to be talked about.
Set retarders are additives that slow the hydration rate and heat of cement and gypsum, and prolong the setting time. The purpose of adding retarder in commercial concrete is to prolong the hydration and hardening time of cement so that the new mixed concrete can maintain plasticity for a longer time, so as to adjust the setting time of the new mixed concrete.
1. The impact on strength: Excessive mixing will cause concrete 24 hours or even 72 hours is still not solidified, thus affecting the need for early strength of concrete and delaying the construction progress. There is no obvious influence on the concrete of proper age.
2. The impact on shrinkage: Moderate use has no obvious effect on shrinkage. When excessive use can cause coping concrete because moisture evaporates excessive generation dry crack contraction and contraction crack.
3. The impact on antifreeze durability: The antifreeze durability of concrete mixed with retarder is similar to that without retarder.
Air entraining agent:
The air entraining agent is a hydrophobic surface-active agent, dissolved in water after joining the concrete mixture, in the mixing process can produce a large number of tiny bubbles.
Air entraining agents can improve the workability, water retention, and cohesion of concrete mixture, improve the fluidity of concrete, and introduce a large number of admixtures evenly distributed, closed, and stable small bubbles in the mixing process of concrete mixture.
The main varieties of air entraining agents include rosin resin, alkyl and alkyl aromatic sulfonic acid, fatty alcohol sulfonic acid, saponin and protein salt, petroleum sulfonic acid, and so on. The commonly used dosage is cement weight 50 ~ 500ppm. Air entraining agent is mainly used for structures with high freezing resistance requirements, such as concrete dams, road surfaces, bridge decks, aircraft yard track surfaces, and other large areas vulnerable to freezing.
The accelerating agent is a kind of additive that can make concrete quickly set and harden when added to concrete. The main types are inorganic salts and organic species. Powdery solid, its admixture dosage accounts for cement dosage in concrete only 2% ~ 3%, but can make concrete in 5min initial coagulation, accelerating agent in 12min condensation. In order to achieve the purpose of rush repair or fast condensation of concrete in the tunnel. It is an indispensable additive in the shotcrete construction method. Their function is to speed up the hydration and hardening of cement, forming sufficient strength in a very short period of time to ensure the requirements of special construction.
Suppliers of Concrete Additives
TRUNNANO is a reliable concrete additives supplier with over 12-year experience in nano-building energy conservation and nanotechnology development.
If you are looking for high-quality concrete additives, please feel free to contact us and send an inquiry. (firstname.lastname@example.org)
We accept payment via Credit Card, T/T, West Union, and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.
The United States urges the U.N. Security Council to impose additional sanctions on North Korea in response to its latest ballistic missile launch, including a ban on tobacco and oil exports to North Korea and a blacklist of the Lazarus hacking group.
The United States circulated the draft to the 15 members of the Security Council this week. It was not immediately clear if or when a vote would take place. A resolution requires nine "yes" votes and no vetoes from Russia, China, France, Britain, or the United States.
Russia and China have already voiced opposition to tightening sanctions in response to Pyongyang's launch of an intercontinental ballistic missile last month -- the first since 2017.
U.S. and South Korean officials and analysts also say there are growing indications that North Korea may soon conduct its first nuclear weapons test since 2017, too.
The U.S. -drafted U.N. resolution would expand the ban on ballistic missile launches to include cruise missiles or "any other delivery system capable of delivering a nuclear weapon."
The deal would halve crude oil exports to North Korea to 2 million barrels a year and refined oil exports to 250,000 barrels a year. The resolution also seeks to ban North Korea's export of "fossil fuels, mineral oils, and their distilled Concrete Additive are estimated to be influenced by international political situation changes.